A laser-ultrasonic composite fabrication method for microstructure arrays

Abstract

This invention discloses a laser-ultrasonic composite machining method for microstructure arrays, belonging to the field of laser precision machining technology. Addressing the problems of poor surface quality, low machining accuracy, and low efficiency in microstructure arrays of rotating parts, this invention proposes an integrated laser-ultrasonic composite machining method for microstructure array positioning, machining, and inspection. After determining the configuration of each component, a probe is used to directly contact and measure the surface of the rotating part, acquiring high-precision three-dimensional contour information of the workpiece and generating a point cloud model. By matching the microstructure array pattern with the point cloud model, the position of the microstructure array is accurately located, and the microstructure array machining process is planned. Focusing lens laser-ultrasonic composite machining improves the internal and external surface quality and machining accuracy of the microstructure; multi-beam parallel processing improves the microstructure fabrication efficiency; and a CCD camera is used for online detection and adjustment of the microstructure array position information. The method disclosed in this patent achieves laser-ultrasonic composite machining of microstructure arrays with high surface quality, high machining accuracy, and high efficiency.

Description

Technical Field

[0001] This invention provides a laser-ultrasonic composite processing method for microstructure arrays, belonging to the field of laser precision processing technology. Background Technology

[0002] Radar radome microstructures are an important barrier to achieving stealth in specific frequency bands for aircraft. With the rapid development of high-end fields such as aerospace and defense, higher requirements have been placed on the surface quality, precision and processing efficiency of radar radome microstructure arrays. Traditional ceramic-based radome microstructure preparation methods such as film transfer and printed electronics have problems such as poor applicability, low processing precision and efficiency. In recent years, laser processing technology has developed rapidly, with a wide processing range and low requirements for processing conditions.

[0003] Patent application number 202210898221.X, entitled "A Macro-Micro Combined Five-Axis Linkage Femtosecond Laser Processing Equipment," provides a macro-micro combined five-axis linkage femtosecond laser processing equipment. It utilizes a five-axis mechanical motion system to adjust the positioning and attitude of a large-range laser beam, enabling laser hole drilling of complex parts. However, due to the thick recast layer, it cannot accurately position and detect feedback on the workpiece. Patent application number 202110668802.X, entitled "Laser Equipment and Method for Automatic Processing Based on 3D Vision Online Measurement Guidance," proposes a laser equipment and method for automatic processing based on 3D vision online measurement guidance, capable of online... Measuring complex components and then guiding laser processing is one approach, but visual measurement, being non-contact, suffers from low overall accuracy. Furthermore, ablated particles and debris can re-enter the workpiece surface, affecting surface smoothness and microstructure processing precision. Patent application number 201610922220.9, "A Multi-Light Source, Multi-Functional, Multi-Axis Laser Processing Head and Equipment," proposes a high-efficiency laser precision processing method and equipment based on a multi-axis linkage CNC machine tool. This method dynamically tracks and focuses the laser focal point during processing, using closed-loop feedback to adjust laser power, enabling high-speed processing of three-dimensional precision patterns on the workpiece surface. However, it lacks workpiece contour measurement and pattern preparation planning. Additionally, single-laser processing struggles to avoid issues such as thick recast layers, low surface accuracy, and low efficiency.

[0004] Laser-ultrasonic composite processing technology introduces an ultrasonic energy field into a laser energy field, causing the material to be simultaneously subjected to photons, acoustic flow effects, and cavitation effects for removal, thus improving processing quality and efficiency. Compared to single laser processing, it offers unique advantages. To achieve high-quality, high-efficiency laser-ultrasonic composite processing of microstructure arrays for components such as radomes, the integration of motion control systems, optical systems, ultrasonic vibration systems, and online detection systems is required. Therefore, there is an urgent need for a high-efficiency, high-precision laser-ultrasonic composite processing method that integrates positioning, processing, and detection to fabricate microstructure arrays on the surface of radomes.

[0005] This invention proposes a laser-ultrasonic composite machining method for microstructure arrays. A working platform, a laser-ultrasonic composite machining device for optical shaping, a CCD camera, rotating parts, and a contact measurement device move in synergistic motion to achieve high-precision contact measurement of the three-dimensional contours of rotating parts, precise positioning and machining planning of the microstructure array, cross-scale laser-ultrasonic composite machining, and online detection and feedback of position information. The focusing lens laser-ultrasonic composite machining enhances the phototube effect and optical honing during laser processing, making the inner surface of the microstructure array smoother, while reducing the heat-affected zone and spatter height, improving the surface quality and machining accuracy of the microstructure. Multi-beam parallel machining technology can process multiple microstructures simultaneously, improving processing efficiency. Through integrated positioning-machining-detection laser-ultrasonic composite machining, the level of automation, microstructure surface quality, machining accuracy, and efficiency are all improved, which has significant theoretical and practical application value for microstructure array machining. Summary of the Invention

[0006] This invention provides a laser-ultrasonic composite processing method for microstructure arrays. The method involves a working platform, a laser-ultrasonic composite processing device for optical shaping, a CCD camera, rotating parts, and a contact measuring device that move in synergy to accurately measure and acquire the three-dimensional contour data of the rotating parts. Through digital-analog matching, the laser-ultrasonic composite processing path of the microstructure array is planned. During the processing, the position information of the microstructure array is detected and fed back online, which improves the surface quality, processing accuracy, and efficiency of the microstructure array of rotating parts.

[0007] The technical solution adopted in this invention is as follows.

[0008] 1) Determining the configuration of each component: Based on the surface characteristics of the rotating parts where the microstructure array is located, determine the configuration of the working platform, the optical shaping laser ultrasonic composite processing device, the CCD camera, the rotating parts, and the contact measurement device.

[0009] 2) Acquisition of workpiece 3D contour information: The working platform drives the rotating parts and the contact measuring device to move in coordination. The contact measuring device directly contacts the surface of the rotating parts using a probe measurement method. As the rotating parts rotate with the indexing, the precise position information of the rotating parts is measured and recorded online, and the 3D contour information of the rotating parts is obtained by analysis.

[0010] 3) Laser-ultrasonic composite processing path planning: Based on the acquired 3D contour information of the workpiece, a point cloud model of the rotating parts is generated. The microstructure array pattern is matched to the point cloud model of the rotating parts to generate a point cloud model after the microstructure array pattern is prepared. The specific processing parameters of each component are selected. According to the precise position information of the rotating parts, the optical shaping laser-ultrasonic composite processing device acts on the microstructure array area along the generatrix of the rotating parts in a small area. With the optical shaping laser-ultrasonic composite processing device and the rotating parts linked, the preparation of the microstructure array of the rotating parts is gradually completed.

[0011] 4) Microstructure array position information detection and adjustment: During the processing, the CCD camera detects the position information of the microstructure array on the surface of the rotating parts online, and feeds the data back to the control system to further regulate the linkage between the optical shaping laser ultrasonic composite processing device and the rotating parts, thereby avoiding positional deviation after error accumulation.

[0012] 5) Laser-ultrasonic composite processing of microstructure arrays: Based on the above steps, the working platform, the optical shaping laser-ultrasonic composite processing device, the CCD camera, the rotating parts, and the contact measuring device move in coordination to achieve high-precision, high-quality, and high-efficiency laser-ultrasonic composite processing of microstructure arrays of rotating parts.

[0013] The optical shaping laser-ultrasonic composite processing device and the CCD camera are mounted on the working platform, and their relative positions remain fixed during the microstructure array fabrication process. The optical shaping laser-ultrasonic composite processing device includes a digital micromirror array, an ultrasonic vibration device, a support frame, a focusing lens, and a laser emitter. The ultrasonic vibration device adopts a cylindrical hollow structure inside, and the focusing lens is horizontally fixed at the front end of the ultrasonic vibration device. The ultrasonic vibration device drives the focusing lens to vibrate at high frequency. The laser emitted by the laser emitter is reflected by the digital micromirror array, passes vertically through the hollow structure inside the ultrasonic vibration device, and acts on the rotating parts through the focusing lens.

[0014] The depth of field of the CCD camera is no less than the amplitude of the ultrasonic vibration device. The laser focus after laser-ultrasonic composite acts on the surface of the rotating parts, and the vibration position of the focus is within the depth of field of the CCD camera.

[0015] The laser emitter generates femtosecond-level lasers with a power of 20-60 W, a repetition rate of 100-200 kHz, a pulse width of W≤250 fs, a beam quality of M2≤1.3, and a power stability of RMS≤2%. The ultrasonic vibration device has a vibration frequency of 20-50 kHz and an amplitude of 5-10 μm. The laser-ultrasonic composite enhancement of the laser action with the optical tube effect and optical honing effect makes the inner surface of the processed microstructure smoother, while reducing the heat-affected zone and spatter height of laser processing, thus improving the surface quality and processing accuracy of the microstructure.

[0016] The digital micromirror array has 128GB of onboard memory and a frame rate of 50 kHz, enabling multi-beam parallel single-exposure rapid processing for light field shaping, breaking through the processing efficiency bottleneck of single beams.

[0017] The working platform has X / Y / Z axis travel ≥600 / 600 / 500mm, A axis ≥±110˚, C axis ≥360˚, X / Y / Z axis positioning accuracy: ≤±3 μm, A\C axis positioning accuracy: ≤±5", which meets the requirements for large-scale high-precision machining of microstructure arrays of rotary parts.

[0018] This invention has the following significant advantages: 1. The working platform, the optical shaping laser-ultrasonic composite processing device, the CCD camera, the rotating parts, and the contact measuring device move in synergy to accurately acquire the three-dimensional contour of the workpiece. The microstructure array pattern is matched with the point cloud model to plan the laser-ultrasonic composite processing scheme. Online detection and feedback of the microstructure array position information allow for integrated positioning, processing, and detection of microstructures, resulting in a high degree of automation and easy control over the microstructure array preparation accuracy. 2. The focusing lens laser-ultrasonic composite process enhances the phototube effect and optical honing during laser processing, making the inner surface of the microstructure array smoother. It also reduces the heat-affected zone and spatter height during laser processing, improving the surface quality and processing accuracy of the microstructure. The multi-beam parallel processing technology allows for the simultaneous processing of multiple microstructures, increasing processing efficiency. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a laser-ultrasonic composite processing method for a microstructure array according to the present invention.

[0020] Figure 2 This is a schematic diagram of a laser-ultrasonic composite processing device for a microstructure array laser-ultrasonic composite processing method according to the present invention.

[0021] Figure 3 This is a gantry milling machine diagram illustrating a laser-ultrasonic composite machining method for a microstructure array according to the present invention.

[0022] Figure 4 This is a detailed implementation diagram of a five-axis precision machine tool for a laser-ultrasonic composite machining method for a microstructure array according to the present invention. Detailed Implementation

[0023] Figure 3 and Figure 4 This is a specific embodiment of the laser-ultrasonic composite processing method for this microstructure array, which is described below in conjunction with... Figure 3 and Figure 4 The present invention will be further described below.

[0024] Example 1

[0025] See Figure 3The laser-ultrasonic composite fabrication method for this microstructure array specifically includes the following steps:

[0026] 1) The working platform 1 is a gantry machine tool, the rotary parts 4 are antenna covers, which are installed on the horizontal turntable of the gantry machine tool; the optical shaping laser ultrasonic composite processing device 2 and the CCD camera 3 are installed on the same Z-axis of the gantry machine tool, and their installation positions are fixed and their movement modes are the same; the contour measuring device 5 is installed on another Z-axis of the gantry machine tool.

[0027] 2) The gantry machine tool drives the radome and the contact measuring device 5 to move in coordination. The contact measuring device 5 directly contacts the surface of the radome using a probe measurement method. As the radome rotates with the indexing, it measures and records the precise position information of the radome online and analyzes and obtains the three-dimensional contour information.

[0028] 3) Based on the acquired 3D contour information, a point cloud model of the radome is generated. The microstructure array pattern is a large-format circular dot matrix. The microstructure array pattern is matched to the radome point cloud model to generate a point cloud model after the microstructure array pattern is prepared. The laser power of the laser emitter 10 is selected as 60 W, the repetition frequency is 100 kHz, the pulse width is 250 fs, and the vibration frequency of the ultrasonic vibration device 7 is 20 kHz with an amplitude of 10 μm. According to the precise position information of the radome, the optical shaping laser ultrasonic composite processing device 2 acts on the microstructure array area of ​​the radome's generatrix. After preparing a column of dot matrix patterns along the generatrix, the radome is rotated in sections, and the next column of dot matrix microstructures is prepared along the generatrix again, gradually completing the preparation of the microstructure array on the surface of the radome.

[0029] 4) The depth of field of the CCD camera 3 is 20 μm. During the processing, the position information of the large-format circular dot array on the surface of the radome is detected online, and the data is fed back to the control system to further adjust the working parameters of the optical shaping laser ultrasonic composite processing device 2 or the rotation index of the radome to avoid positional shift after the preparation of multiple rows of dots.

[0030] 5) Based on the above steps, the gantry machine tool, the laser ultrasonic composite processing device (2), the CCD camera (3), the radome, and the contact measuring device (5) work together to realize the laser ultrasonic composite processing of a large-format circular dot matrix on the surface of the radome.

[0031] Example 2

[0032] See Figure 4 The laser-ultrasonic composite fabrication method for this microstructure array specifically includes the following steps:

[0033] 1) The working platform 1 is a five-axis precision machine tool, and the rotary component 4 is an antenna cover, which is installed on the horizontal turntable of the five-axis precision machine tool; the optical shaping laser ultrasonic composite processing device 2, the CCD camera 3 and the contour measuring device 5 are installed on the Z-axis of the five-axis precision machine tool. The optical shaping laser ultrasonic composite processing device 2 and the CCD camera 3 are fixed in their installation positions and move in the same way.

[0034] 2) The five-axis precision machine tool drives the radome and the contact measuring device 5 to move in coordination. The contact measuring device 5 directly contacts the surface of the radome using a probe measurement method. As the radome rotates with the indexing, it measures and records the precise position information of the radome online and analyzes and obtains the three-dimensional contour information.

[0035] 3) Based on the acquired 3D contour information, a point cloud model of the radome is generated. The microstructure array pattern is a large-format circular arrangement of sinusoidal grooves. The microstructure array pattern is matched to the radome point cloud model to generate a point cloud model after the microstructure array pattern is prepared. The laser power of the laser emitter 10 is selected as 60 W, the repetition frequency is 100 kHz, the pulse width is 250 fs, and the vibration frequency of the ultrasonic vibration device 7 is 20 kHz with an amplitude of 10 μm. According to the precise position information of the radome, the optical shaping laser ultrasonic composite processing device 2 moves along the radome generatrix, the radome rotates in an indexing manner, and the two couple to form a sinusoidal motion trajectory. After preparing a series of sinusoidal grooves, the radome rotates in an indexing manner, and the optical shaping laser ultrasonic composite processing device 2 and the radome move in coordination to prepare the next series of sinusoidal grooves, gradually completing the preparation of the microstructure array of the rotating component 4.

[0036] 4) The depth of field of the CCD camera 3 is 20 μm. During the processing, the position information of the large-format circumferential dot matrix on the surface of the rotating parts 4 is detected online, and the data is fed back to the control system to further adjust the working parameters of the optical shaping laser ultrasonic composite processing device 2 or the rotation index of the radome to avoid positional deviation after the preparation of multiple sinusoidal grooves.

[0037] 5) Based on the above steps, the five-axis precision machine tool, the optical shaping laser ultrasonic composite processing device (2), the CCD camera (3), the radome, and the contact measuring device (5) work together to realize the laser ultrasonic composite processing of large-area circular sinusoidal grooves on the surface of the radome.

Claims

1. A laser-ultrasonic composite processing method for microstructure arrays, characterized in that: Includes the following steps: 1) Determining the configuration of each component: Based on the surface features of the rotating parts where the microstructure array is located, determine the configuration of the working platform (1), the optical shaping laser ultrasonic composite processing device (2), the CCD camera (3), the rotating parts (4), and the contact measurement device (5); The optical shaping laser ultrasonic composite processing device (2), the CCD camera (3), the rotating parts (4), and the contact measurement device (5) are installed on the working platform (1). During the microstructure array preparation process, the relative positions of the optical shaping laser ultrasonic composite processing device (2) and the CCD camera (3) remain fixed. 2) Acquisition of workpiece three-dimensional contour information: The work platform (1) drives the rotary parts (4) and the contact measuring device (5) to move together. The contact measuring device (5) directly contacts the surface of the rotary parts (4) using the probe measurement method. As the rotary parts (4) rotates, the precise position information of the rotary parts (4) is measured and recorded online, and the three-dimensional contour information of the rotary parts (4) is analyzed and obtained. 3) Laser-ultrasonic composite processing technology planning: Based on the obtained three-dimensional contour information of the workpiece, a point cloud model of the rotating part (4) is generated, and the microstructure array pattern is matched to the point cloud model of the rotating part (4) to generate the point cloud model after the microstructure array pattern is prepared; the specific working parameters of each component are selected, and according to the precise position information of the rotating part (4), the optical shaping laser-ultrasonic composite processing device (2) acts on the microstructure array area of ​​the busbar of the rotating part (4) in a small area. With the linkage of the optical shaping laser-ultrasonic composite processing device (2) and the rotating part (4), the preparation of the microstructure array of the rotating part (4) is gradually completed. 4) Microstructure array position information detection and adjustment: During the processing, the CCD camera (3) detects the position information of the microstructure array on the surface of the rotating parts (4) online, and feeds back the data to the control system to further regulate the linkage between the optical shaping laser ultrasonic composite processing device (2) and the rotating parts (4), thereby avoiding position shift after error accumulation; 5) Laser-ultrasonic composite processing of microstructure arrays: Based on the above steps, the working platform (1), the optical shaping laser-ultrasonic composite processing device (2), the CCD camera (3), the rotating parts (4), and the contact measuring device (5) work together to realize the laser-ultrasonic composite processing of the microstructure array of the rotating parts (4).

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